In the old days, when Dikembe Mutombo’s sharp elbow smacked into the eye of Kenyon Martin, look out. Martin’s volcanic eruption would have spilled over onto the court.

These are better days for Martin, and last night he responded to Mutombo’s aggression with nothing more than a hard foul meant to send a message.

“When he first came into the league, guys would try to get in his head and he would respond the way he did and it cost him a lot of money and he got suspended,” Nets guard Lucious Harris said.

“Now he’s learned, ‘Let me get in their head and make them do something stupid to me.’ “

There was nothing stupid out of Martin, but there was plenty that qualifies as splendid. He led the Nets in points (22), rebounds (16) and controlled aggression as this rapidly-deteriorating playoff encounter heads to the Garden with the Nets a resounding 2-0 series leader after a 99-81 whipping of the Knicks at the Meadowlands.

Combative and dominant all game, Martin in the third quarter did not overheat after getting clocked by Mutombo, who promised Game 2 would be “a war” after Tim Thomas was injured by a Jason Collins flagrant foul in the opener.

“He elbowed me in the eye, I told the ref,” Martin said.

On the very next play, with 5:02 left in the quarter Martin looked for payback. He not only fouled Mutombo but also took a whack at the ball, slamming Mutombo’s arms for good measure.

For that, Martin was hit with a technical foul.

“I just told him it was unnecessary . . . I don’t need that,” said Mutombo, who sported a bloody red scratch on his face.

“I just wanted to foul him, I didn’t want to get the tech,” Martin said. “The emotions were running. It happened, it’s over.”

It was over, which says something about Martin. “Kenyon’s grown in all aspects of his game,” Jason Kidd said.

Martin’s restraint was more than matched by his play, which coach Lawrence Frank dubbed “superb.”

The main concern coming into the postseason was the health of Martin and Kidd, and thus far both have been sensational.

For now, the tendinitis problem Martin had in his left knee is a thing of the past. So are his hot-headed tendencies.

“If something was malicious or they try to hurt somebody, then you have to respond in the right way,” Martin said. “We won the game, that shuts all that up.”